Tea flavan-3-ols as modulating factors in endoplasmic reticulum function

• Published in: Nutrition research (New York, N.Y.) Vol. 31; no. 10; pp. 731 - 740
• Main Authors: Révész, Katalin, Tüttő, Anna, Szelényi, Péter, Konta, Laura
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.2011; Elsevier
• Subjects: analogs & derivatives; Animals; Anticarcinogenic Agents; Anticarcinogenic Agents - pharmacology; Antineoplastic Agents, Phytogenic; Antineoplastic Agents, Phytogenic - pharmacology; Biological and medical sciences; Biological Transport; Biological Transport - drug effects; biomedical research; biotransformation; Biotransformation - drug effects; calcium; Calcium Signaling; Calcium Signaling - drug effects; carcinogens; Carcinogens - pharmacokinetics; Catechin; Catechin - analogs & derivatives; Catechin - pharmacology; chemistry; chemoprevention; diabetes mellitus; drug effects; Drug Resistance, Neoplasm; Drug Resistance, Neoplasm - drug effects; drugs; endoplasmic reticulum; Endoplasmic Reticulum - drug effects; Endoplasmic Reticulum - metabolism; epigallocatechin; Feeding. Feeding behavior; flavanols; Flavonoids; Flavonoids - pharmacology; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Gluconeogenesis; Gluconeogenesis - drug effects; glucose; Glucose production; Glucuronidation; Glucuronides; Glucuronides - metabolism; Glycosylation; Glycosylation - drug effects; Green tea; homeostasis; Humans; Hypoglycemic Agents; Hypoglycemic Agents - pharmacology; mechanism of action; metabolism; neoplasms; pharmacokinetics; pharmacology; Polyphenols; Protein Processing, Post-Translational; Protein Processing, Post-Translational - drug effects; protein synthesis; risk; Tea; Tea - chemistry; Vertebrates: anatomy and physiology, studies on body, several organs or systems; viability; G6P; UGT; Glucuronidation; ATPase; EGCG; PLC; BiP; ECG; RyR; Glycosylation; SERCA; ER; ERAD; G6PT; G6Pase; UPR; Polyphenols; Glucose production; Green tea; epigallocatechin gallate; immunoglobulin heavy chain binding protein; epicatechin gallate; G6P translocase; adenosine triphosphatase; sarco/endoplasmic reticulum calcium ATPase; glucose-6-phosphate; ryanodine receptor; phospholipase C; UDP-glucuronosyltransferase; ER-associated degradation; unfolded protein response; endoplasmic reticulum; glucose-6-phosphatase; Vertebrata; Polyphenol; Mammalia; Glucose; Endoplasmic reticulum
• ISSN: 0271-5317; 1879-0739; 1879-0739
• DOI: 10.1016/j.nutres.2011.09.008

Regular green tea consumption has been shown to reduce the risk of cancer and diabetes mellitus. These effects are attributed to tea flavan-3-ols, especially to epigallocatechin gallate; however, the molecular targets and mechanisms of action are still subject of extensive research. The special roles of the endoplasmic reticulum (ER) in biotransformation, protein synthesis, calcium homeostasis, and glucose production make this organelle a potential target of the antitumor and antidiabetic effects of tea flavan-3-ols. The purpose of this review is to present evidence for the biologic actions of tea flavan-3-ols on specific ER targets associated with normal function and disease. Reactivation of chemical carcinogens can be reduced by tea flavan-3-ols through inhibition of glucuronide transport across the ER membrane. Catechins modulate Ca 2+ release from the ER lumen and interfere with glycoprotein maturation, which can lead to decreased viability and increased drug sensitivity of tumor cells. Epigallocatechin gallate inhibits glucose transport across the ER membrane, which can underlie the reduction of hepatic glucose production by tea flavan-3-ols. These mechanisms likely contribute to the chemopreventive and glucose-lowering effects of tea catechins. Investigating the effects of flavan-3-ols on ER functions is a promising field of medical and biochemical research to understand disease and improve health.